Example of Dortmunder Westfalenhallen

As part of the modernisation, the old heating system of the Westfalenhallen convention centre in Dortmund was replaced by a new heating system in 2008, which includes one gas condensing boiler (970 kW) and three steel boilers having different outputs (1,900, 3,050 and 5,200 kW). By grading the outputs of the boilers used, the energy-efficient gas-fired condensing boiler is used as the main boiler for long operating duration, whereas the three downstream boilers are operated based on demand. The efficiency of the overall heating system was improved from 83 percent to 92 percent due to the modernisation. The intelligent functioning of the new heating system with a modern building services management system and a total of 40 heat meters distributed over the premises also enables the heat to be supplied in a flexible and demand-based manner. Using the condensing boiler and the demand-based control, the annual fuel consumption was reduced by two million kWh, implying that the operator can save energy costs of around € 100,000 per year. The return on capital of this energy saving investment is 20 percent.

Reduction in energy consumption

2,000,000 kWh / year

Energy savings in percentage

11 %

CO2 reduction*

488 tons / year



Cost reduction

€100,000 / year

Return on capital

20 %


The following equivalent values as per Gemis are the basis for all the examples: Natural gas 244 g CO 2  / KWh.

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